Diaphragm for talking-machines.



THOMAS CHALMERS, 0F CIR-EWE, ENGLAND.

DIAPHRAGM FOB TALKING-MACHINES.

Specification of Letters-Patent.

Patented Mar. 25, 1919.

Applcatonled May 2, 1916. Serial No. 94,870.

To f/ZZ ywhom Ait may concern: i

Be it known that I, THOMAS GHALMERS, a subject of the King of Great Britain and Ireland, and a resident of Creive, in the county of Chester, England, have invented certain new and useful Imlirovements in Diaphragms for Ialking-hlachines and the like, of which the following is a specification. l

This invent-ion relates to diaphragins for telephones, transmitters, grainophones and the like and has for its object to provide irnproved means ivhereby such diaphragme; may be tensioned or timed to give the most suitable note without interfering with the vibrating area.

The invention resides, essentially, in increasing the thickness of a telephone, transmitter, gramophone or like diaphragm at a plurality of points at ai unifor/ni distance from its center. By this means the sound waves or vibrations set up at the center of the diaphragm are encountered or inter-n rupted by the thickened portions and prevented from quickly inassing in concentric circles at the periphery of the diaphragm where their value is a minimum and are redirected or focused back to the center with the result that the waves are intensified and a louder and clearer note is produced.

The. thickened portions may be formed on the front or the rear surface of the diaphragm or they may be formed on both the front and rear surfaces.

The thickened portions .may be integral with the diaphragm or they may be constituted by sepai'ate disks, rings, plates, bars, rods or the like'attached to one or both surfaces of the diaphragm. Further, the thickened portions when separate may be of soft iron, tin, brass, lead, solder or other suitable metal, or ebonite, vulcanite, wood, liber or other appropriate mater'I l. They are however, preferably of metal.

In the accompanying drawings Figure 1 is a front View of a diaphragm and Fig. 2 a side view thereof illustrating one embodiment of the invention. Fig. 3 is a side view showing another embodiment. Figs. 4 and 5, 6 and 7, and 8 and 9 are similar views to Figs. l and 2 respectively, illustrating further embodiments of the invention. Fig. 10 is a front view and Fig. l1 a section of another embodiment.

Fig. l2 is a section of a still further em-A bodiment.

Referring lirst to Figs. l and 2,. ,accord ing to this embodiment the diaphragm a has arranged on and secured to its front face or surface, between its center and outer periphery, a. plurality of flat disks Z). The faces of the disks b next the diaphragme are made dead true so that the whole of said faces are in actual contact with the diaphragm. The disks Z) are att-ached to the diaphragm by screws o or any other suitable means. The outer edges (l of the disks are concentric to the periphery of the diaphragm and their inner edges e are conveX or rounded as shown.

The disks b canse a thickening of the diaphragm a at the places here they are 'located and the effect of these thickenings is, L

In Figs. 6 and 7 the thickening disks 7)- are of flat ring or annular form while lin Figs. 8 and 9 they are of pyramidal construction.

In all the above embodiments the thickenings Z) are separate from the diaphragm and attached thereto by screws c or other suitable means as described in reference to Figs. l and 2.

In some cases, however, c. g. when the diaphragm is of carbon, the thickenings may be integral with the diaphragm as shown in Figs. 10 and ll. Or the thickenings may be formed by indenting the diaphragm and filling in the resulting recesses with suitable material as illustrated in Fig. 12.

The thickenings b may be arranged on the rear face or surface of the diaphragm a instead of on the front face or surface thereof. O* as shown. in Fig. 3, the thickenings may be arranged on both the front and rear faces or surfaces of the diaphragm.

In all cases the number, position, size and thickness or" the thickened portions will depend on the size and thickness of the diay plir gni and will be decided in each case by eXp riment.

vVhen my improved 'focal vdiaphragm is employed in telephones, transmitters and the like a considerable saving can be effected in the amount of copper in'the line.

lVhat l claim is l. A. diaphragm comprising a thin disk having portions thereoi2 of greater thickness i than said disk proper, and said thickened portionsvbeinglocated between the center Iand the periphery of said disk.

2; 'A diaphragm comprising a thin disk having portions thereof of greater thickness than the thickness ot' said disk proper, and

said thickened portions being located loetween the center and periphery of the disk and at uniform distances from the center.

3. A diaphragm comprising a .thin disk having portions thereof of greater thickness than said disk proper, said portions constitilting isolated areas located between the center and the periphery of the. disk and arranged in circular form.

4. A diaphragm comprising: a thin disk having indentations formed therein, and a `member filling each of said indentations and rigidly secured therein.

5. A diaphragm comprising a thin disk having indentations formed therein, and a.

member filling each of said indentations rigidly secured to said diaphragm, said indentations being located between the center and periphery of the disk.

G. A diaphragm comprising a thin disk having indentations formed therein, and a member filling each of said indent-ations rigidly secured to said dialgihragm, said indentations being located between the center and 

